So I got everything to work. I can read/write in windows but I can only get read-only access in linux. I've tried changing the config but it doesn't seem to change anything. The files are marked as if they have root:root ownership.

What do you mean with read only access from linux? The howto is for anabling Windows workstations to store their data on the samba server, its not an NFS howto for connecting linux workstations to the server.

If your files are marked as root:root owner, then you used the wrong user in windows. You will have to create a new linux + samba user, the connect with this username and password from windows. Not with the Administrator user. The Administrator is the root user on linux, it is only used in the process of adding your workstation to the domain to authorize you once as admin.

I have both linux and windows computers connecting to the samba server. Like I said everything works fine on the windows computer (read+write, and i do login as a samba user) but on my linux computer I can only read (unless I use sudo).

Also went through the howto (http://www.howtoforge.com/samba_setup_ubuntu_5.10_p4), but at the part when I start the installation of samba with the command:
"apt-get install samba samba-common samba-doc libcupsys2-gnutls10 libkrb53 winbind smbclient" I seem to miss the winbind-packet. Get the response (translated from Swedish):
"Packet winbind is not avaiable, but another packet refers to it. This usually means that the packet is missing, is obsolete or is avaiable from other sorces.
E: Packet winbind has no installationcandidate"

Tried to google for an answer, but didn´t find any, can anyone here help me?
Thanks!

Also went through the howto (http://www.howtoforge.com/samba_setup_ubuntu_5.10_p4), but at the part when I start the installation of samba with the command:
"apt-get install samba samba-common samba-doc libcupsys2-gnutls10 libkrb53 winbind smbclient" I seem to miss the winbind-packet. Get the response (translated from Swedish):
"Packet winbind is not avaiable, but another packet refers to it. This usually means that the packet is missing, is obsolete or is avaiable from other sorces.
E: Packet winbind has no installationcandidate"

Tried to google for an answer, but didn´t find any, can anyone here help me?
Thanks!